iptables mangle

I created a firewall-start script with two statements, uploaded it to the proper location, restarted the firewall and all was well. I then rebooted the router and it never came up fully. Eventually, I caught a brief window and was able to delete the firewall-start script file and the router has...

I am trying to get traffic from one device to be available at a second device so I can sniff for certain packets. The traffic from the first device still needs to continue, not just be forwarded to the second device. I believe these are the iptables entries I need to do this. However, entering...